1. Field of the Invention
The present invention relates to a communication system, a relay apparatus, an end system, and a communicating method, in which a connection via a plurality of relay apparatuses is established between end systems for communicating and data is communicated. More particularly, the invention relates to a communication system, a relay apparatus, an end system, and a communicating method, in which upon occurrence of a path fault, it is tried to establish a connection by another path without notifying an application on a communicating source side of a communication error.
2. Description of the Related Arts
Hitherto, in a generally used routing protocol as well as the Internet by which a connection via a plurality of multiplexed relay apparatuses is established and data communication is performed between end systems, the respective relay apparatuses exchange routing information in addition to communication data, thereby selecting the optimum path. In the routing protocol, a verification packet is transmitted at a predetermined period in order to monitor a network, thereby detecting a path fault such as a relay apparatus error or the like. In a large-scale network comprising multi-stage relay apparatuses, there is a case where it requires a predetermined period until routing information is propagated after the path fault occurred.
In such a large-scale network which needs the multi-stage relay apparatuses to a partner destination system, in the case where a path fault is detected and it takes a time of a certain extent until routing information is updated by the routing protocol, if the application of the end system transmits communication data by using the fault path during such a period of time, the connection cannot be established and an error occurs on the application. Therefore, a communicating request or the like is issued again on the application and the path is switched to a new path excluding the erroneous path, thereby newly establishing a connection. There is such a problem that it takes time until communication (business) is started.